Elevator dispatching system



Nov. 11, 1941. w, F, EAMES ELEVATOR DISPATCHING SYSTEM 3 Sheets-Sheet 2 Filed Nov. 6, 1957 v m v m p r INVENTOR INN/20772 F Eamas.

WITNESSES:

Patented Nov. 11, 1941 ELEVATOR DISPATCHING SYSTEM William F. Eames, Pittsburgh, Pa., assignor to Westinghouse Electric Elevator Company, Jersey City, N. J., a corporation of Illinois Application November 6, 1937, Serial No. 173,193

Claims. (Cl. 177 336) My invention relates to dispatching systems for a group of elevators and more particularly to a mechanism for regulating the timing of the interval at which the cars are signalled to leave the dispatching floors.

One object of my invention is to so regulate the signals for dispatching elevators from a given floor that on the average a predetermined number or fractional number of elevators will be found standing at the floor.

Another object of my invention is to automatically regulate the timing of the interval so that the. most efficient service from the bank of. cars will result.

Another object is to have the arrival and departure of the cars from a given floor regulate the interval timing of the dispatcher.

A further object is to shorten the interval auto matically when trafiic conditions tend to accumulate more cars at a given floor than is found necessary for best service to the other floors.

A still further object is to lengthen the interval automatically if fewer cars are found at a given floor than is found necessary for best service at that floor.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

Figure 1 is a diagrammatic representationof-a' group of elevators embodying my improved dispatching system. 7

Fig. 2 is a top plan-view of the dispatching timer embodied in the system shown in Fig. 1.

Fig. 3 is a top plan view of the motor driven rheostat for controlling the speed of the motor of Fig. 2. s

Fig. 4 is a straight line drawing of the circuits for the dispatching system shown in Figs. 1 to 3; and

Fig. 4A is a diagrammatic representation of the relays and associated contact members embodied in Fig. 4.

The illustration of the relays in Fig. 4A shows them with their coils and contact members disposed in the same vertical positions they occupy in Fig. 4. By placingFi'g. 4A beside Fig. 4, any contact or coil may be readily located in Fig. 4 by following a horizontal line across fromv its position in Fig. 4A. Fig. 4A is a key to the coil position and to the kind of contacts, the position and number associated with any given coil of Fig. 4.

For convenient reference the main relays and parts are indicated in the drawings by the follow ing reference letters:

B Interval adjusting relay. IC to 40 Terminal relays. 1 F 1 -Flicker relay.

I-l'L Limit switch for rheostat motor.

I i Interval relay.

LL 'Limit switch for rheostat motor.

IN to 4N Next signal relays.

[R to 4R. Sequence relays.

IS to 48 Start signal relays.

SS Stop sequence relay.

TI to T3 Timer contacts.

TSI to TS lTerminal switch contacts.

Referring more particularly'to the drawings, in Fig. 1, I have shown four cars IE, 2E, 3E and 4131 serving five floors. It will' be evident that my system can be used with any number of cars or floors. Duplicate. installations may be made at other .than the lowest floor and the arrival and departure of the cars from this floor can be regulated" independently of the action occurring at the lowest floor or any other floor. Switches TSl'to 'IS4 shown in this case at the lowest floor are operated by a cam 8 on each of the various cars. The dispatching mechanism to be described is usually located in the pent house (not shown) and it operates signals lL to 4L to advise the operators of the respective cars the proper time to leave the dispatching floor.

Fig. 2 shows a plan view of a timing mechanism that may be used in my invention. An adjustable speed motor 24 drives shaft 22a through a speed reducing gear 22. Mounted on shaft 22a are three cams I 'l--l9 and 2|. The angular position of cam I! is adjustable with respect to the positions of cams l9 and 2| for a purpose that will be explained. The cam parts operate on rollers I6, l8 and 2G to open or close contacts T3, T2 and Ti respectively once for each revolution of the shaft.

Fig. 3 shows a plan view of a motor driven rheostat that may be used in my invention. A reversible motor 34 drives a threaded shaft 28 through a speed reducing gear 32. A travelling nut 21 moves backward and forward along the threaded shaft depending on the direction of rotation. A moving contact 29 (not shown in this figurebutshown in Fig. 4) contacts the wires of a resistance winding 26 so that an adjustable amount of resistance is connected between the nut 21 and either end connection of winding 26. Nut 21 has one surface shaped to engage two rollers 30 and 31 which open limit switch con- Thus motor 24 turns continuously at a speed determined by the amount of resistance 23 included in the circuit by contact 29'. Assuming no cars at the dispatching floor, switches TSI to TS4 will be open, relay coils IC to 40 will be deenergized, and, assuming switch I open, coilBwill be deenergized. Under these conditions, motor armature 34 will be energized througha circuit Thus motor 34 will turn in a direction to move travelling nut 21 to slow down motor 24. If motor 34 is allowed to run long enough, limit contact LL will be opened by nut 21- and motor 34 will be stopped. At this time motor 24 will runat its lowest speed and the timinginterval will have its greatest value. g a

Under the assumedconditions relay coil IR will be energized through the circuit LI-IR--3RI2RIL2 Relay IR in picking up will energize coil 2R LI2R-4RI-IRIL2 Contact 2RI will then open the circuit previously traced to coil IR and this coil will be deenergized. However, relay IR does not moveimmediately to the deenergized position as this relay, as well as 2R, 3R and 4R, is provided with a time delay in opening of approximately 1 second. Therefore, about a second will expire before the armature of relay IR will move, and relays IR and 2R will remain in the energized position during this time.

When the armature of relay IR does'drop out, contacts IR2 make a circuit to energize the coil of relay 3R circuit for 3R which drops out after a time dedelay. During this time, relays 3R and 4R are in the energized position.

When the armature of relay 3R. drops out, 0011- tacts 3RI make a circuit to energize coil IR.

LI-IR--3RI-2RIL2 It also interrupts the circuit to relay coil 4R 60 Relay 2R also interrupts the previously traced Assuming that while relays IR and 2R are in the energized position that car IE arrives at the floor. The arrival of car IE closes switch TS! and relay IC is thereby energized The energized relay IC closes its contacts ICI, thus the coil of relay B becomes partially energized through resistor l0,

This relay is one having adjustable pick up and drop out. Assume that at present it is adjusted so that at least two resistors I0 to I3 must be connected in parallel to energize the coil sufficiently to cause it to pick up.

which drops out after a time delay. During this f interval the armatures of relays 4R and IR are in the energized'position. Thus with no car at the floor, relays IR to 4R continue picking up in a sequence requiring about four seconds for the cycle. a

Relay B therefore remains in the deenergized position. Relay IC closes a circuit to energize the coil of relay IN.

1 LIIR32R4--ISI--IN- --IC2L2 "Relay IN lights the signal light IL in car IE I L I lI -IN4L2 indicating to thecar operator that his car is the next to leave the floor and to be prepared to leave on receipt of a start'signal.

Relay IN also energizes coil SS.

Relay SSpartiallyenergizes the coil of relay IR, through circuit LI-IR--38--SSI-L2 sufiicient to prevent the relay armature dropping to the deenergized position.

Relay SS also partially energizes coils 33R and 4R. o

L I--3R--4 USS3L2 L I4R4 ISS4-L2 but not sufiiciently to cause their armatures to move to the energized position. As relay IR can-, notnow drop out, the progression of the cycle of relays IR to 4R is stopped while relay SS is energized. t

As time progresses, motor 34 continues to turn in a direction to insert slowly additional resistance of rheostat 23 into the armature circuit of motor 24. Motor'24 is turning also but as time progresses it turns slower.

Assume now that car 2E arrives at the dispatching floor. Switch T32 is closed-by cam 8 of car 2E. Relay 20 becomes energized through circuit L I-2C'TS 2L2 An additional circuit is now provided to coil B.

LI-2CI--I IBL2 and the combined effect of the currents through coil B is suflicient to cause its armature to move to the energized position. Contacts B3 and B5 opening interrupt the previously traced circuit to motor armature 34 and contacts B4 and B2 establish another circuit in which the direction of the current flowing in armature 34 is opposite to that of the previously traced circuit. Motor 34 therefore reverses its 4 direction of rotation and, as long as relay B is picked up, moves nut 21 in a direction to speed up motor 24, and therefore to reduce thetiming interval.

Assume now that switches TI and T2 are opoperated simultaneously by camsv 2| and I9. Contact TI closes a circuit to relay I.

LI-TI-I-L2 Relay I establishes a self-holding circuit.

LII2IS42S33S34S3-IL2 As motor 24 continues-to turn,, contacts TI and T2 return to their unoperated positions, The closing of terrupts the pick up circuit to relay IN which drops out and itestablishes a circuit to signal lamp IL through flicker relay'F Flicker relay F is of a type that opens and closes its contacts slowly. When the coil is energized contacts Fl open after an interval which deenergizes coil F and lamp IL. .After another interval contacts Fl close and the sequence repeats. Flasher buttons for flashing lights op-.

erate on this principle. The eifect of this is to cause the previous steady signal. of lamp IL to become intermittent which servesasa signal to .the operator of car IE that his Waiting interval is ended and that h should leave the dispatching I As coil IN-has been deenergized, :the circuit to relay coil SS is interrupted which releases .the holding circuit to relays IR to'4R'previously described. Relay IR now drops outafter a shortmi time interval and relay 3R picks up. (Previously described.) As we assumed car' 2E at the floor and relay 2C energized, a circuit is now set up for energizing coil 2N.

which lights signal-2L in car 2E and picks up relay SS to again hold relays IR to IRin their present condition, thatis, relays 2R and BE inienergized position and IR and 4R in deenergized.

position.

If car 3E had been assumedat the dispatching floor instead of car 2E, the relay chain IR to 4R. would have continued until relays'iIR and 4R were in the energized position at "the same time at which time a circuitwould' have been completed to energize relay 3N. Thus. relays IR to 4R constitute a selective mechanism so that only one car will have its next relay energized at a given time so that if several cars are at the dispatching floor only one will be selected to depart next.

Assume car IE operator has closed his door and left the dispatching floor opening switch 'TSI upon receiving the flashing signal to depart. This drops out relay IC which breaks the holding circuit to relay IS previously traced. This stops the intermittent signal in the car. The opening of contact ICI reduces the current through relay B to a point where it drops open. Motor 34 is again reversed and starts lengthening the next timing interval which action will continue until another car arrives at the floor to again pick up relay B through the current fed to the coil through contact 3C'I or 4CI and resistor I2 or I3.

From the foregoing it will beapparent thatif onecar is at the dispatching floor all the time and a second one there half the time, that motor 34 will slow down interval motor 24 half the time and speed it up half the time with a net effect over several periods of operation of no change in interval. Thus we may say that on an average there will be found one and onehalf cars at the dispatching floor.

It should also be evident that, if relay B is adjusted to pick up with the current through one resistor and drop out only on zero current, the interval will be shortened and cars dispatched from the floor at shorter intervals. A balance will occur when there is no car at thedispatching floor half the time and one car there half the time. Therefore, with this adjustment there will be found one car at the dispatching floor half the time if We assume that the cars make their trips and arrive back at this floor with the regularity with which they are dispatched from it, or we may say that on an average there will be found half a car at the dispatching floor. In practice no such regularity occurs but the timer automatically makes incremental adjustmentsof the timing interval in a direction to have this action occur considered over a period oftime.

'I have provided'a switch I5, adjustable cam II operating sWltClTT3, a resistor I4,-and a con- .tact of relay B with which means I can get any desired fraction of a car at the dispatching floor. For instance, I can have the cars receive a dispatch signal, considering the average, as soon-as theyarrive which 'is the shortest practical adjustment or I can have one car receive its dispatch signal just slightly ahead of the average arrival time of a second car so that I will have an average of one car at the dispatching floorv all the time. The former condition will be described, I believe the operation of other combinations will be evident.

Assume now that switch I5 is closedand that cam I! is set to open its associated contact T3 180 of rotation of shaft 22a after contacts'TI and T2 return to their normal positions. Assume also that relay B is adjusted to pick up with the current of one resistor and to drop out with zero current. Under this latter condition with switch I5 open, I'have pointed-out that there will be or-tend to be a car at the dispatching floor half the time. With switch I5 closed when relay B picks up an additional current is fed through coil B namely that flowing through resistor I4 in circuit.

-When car IE now leaves the dispatching floor in response to the dispatch signal and its C relay drops out the circuit to relay B is not interrupted, being held in through the previously traced circuit and relay B remains in its energized position just as if another car were standing at the floor. It will stay in this position for 180 of rotation of timing shaft 22a until contact T3 opens or for half an interval. During this, time the speed of the interval determining motor 24 will be increasing just as it would if there were an actual car at the dispatch floor. Thus the interval will be made shorter and shorter while the circuit T3- I4BII5 of what may be. termed a phantom car is. closed. Abalance will occur when there is an actual or the phantom car at the floor half the time. When this occurs there will. be no car at the floor half an interval and the. phantom. car half an interval, which also is .no car,

or, theoretically thearriving car willbe at the door only long enough to pick up a C relay when it will receive a dispatch signal." In practice it will remain after its dispatching fsignal long enough to discharge and take on passengers before leaving which will in no way disturb the conditions that cause the giving of the dispatch signal at the time of arrival of the car.

I believe it will be evident that the angular position of cam I! when changed will vary the time of the phantom car being at the'floor and that the interval will be adjusted to give the dispatching signal sooner or later, depending on the direction of movement and amount.

' I I believe it Will be evident that, withrelay B adjusted to maintain one and one half cars at the floor and cam ll adjusted to obtain half a car less (180 position previously described) there will be a net efiect maintaining on the average one car at the floor. H I

Although I have illustrated and described only one specific embodiment of my invention, it is tobe understood that modifications thereof and changes thereinmay bemade without departing from the spirit and scope of my invention. a

arrival and departure of the cars at the dispatching floor for operating the signal devices to give starting signals to the cars at intervals which will maintain on the average a predetermined number of cars at the dispatching floor.

2. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals tothe cars at predetermined intervals, and means responsive to the arrival and departure of the cars at the dispatching floor for causing the timing device to change the length of the predetermined intervals sufliciently to maintain on the average a predetermined number of cars at the dispatching floor.

3. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to the cars at predetermined intervals, and means responsive to a desired number of cars at the dispatching floor for causing said timing device to decrease its speed for one-half of the impulse interval and to increase its speed for the other half of the impulse interval and responsive to less than the desired number of cars at the floor to decrease the speed of the timing device for a greater portion of the interval than it increases the speed to thereby increase the length of the interval and thus make more cars available at the floor.

4. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal deing dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to thecars at predetermined intervals, and means responsive to the number of cars at said floor for controlling the timing device to affect the length of the next impulse interval; said means being responsive to a desired predetermined number of cars at said floor for causing the timing device to give equal successive impulse intervals between signals and responsive to more than said desired number of cars at said floor during one interval for causing the timing device to shorten at least two of said intervals.

5. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to the cars at predetermined intervals, and means responsive to no cars at said dispatching floor during one impulse interval for causing the timing device to increase the length of the impulse intervals between at least three consecutive impulses, regardless of the number of cars at said floor during the second interval.

6. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to the cars at predetermined intervals, and means responsive to a desired predetermined number of cars being at said floor during one interval for controlling the timing device to give the next impulse after the same interval as the last, said means being responsive to a less than said predetermined number of cars being at said floor during one of said intervals to cause the timing device to give a subsequent impulse after a longer interval, to thereby increase to said predetermined number of cars on the average the number of cars located at'said floor, regardless of the round trip time of said cars.

7. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device forgiving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to' the cars at predetermined intervals, and means responsive to operation of said first mentioned mechanism for continuously adjusting the speed of the timing device to cause it to give impulses at intervals to keep a predetermined number of said cars on the average stationed at said floor, regardless of the round-trip time of said cars in serving said floors.

8. A dispatching system. for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal vdelvices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to the cars at predetermined intervals, a rheostat for controlling the speed of the timing device, a motor for controlling the rheostat, an interval adjusting relay for reversing the direction of operation of the motor, and means responsive to the presence of a predetermined number of cars at the floor for energizing and deenergizing the relay to control the motor whereby the timing device will be controlled to give dispatching intervals of such length as to keep on the average a predetermined number of cars at the dispatching floor.

9. A dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatching floor, a plurality of signal devices, one for each car, a timing device for giving dispatching impulses at predetermined intervals, means responsive to the arrival of the cars at the dispatching floor and to the operation of the timing device for operating the signal devices to give starting signals to the cars at predetermined intervals, a circuit closing device operable by the timing device, a plurality ofswitches operable by the arrival of the cars at the dispatching floor, one switch for each car, and means responsive to operation of the circuit closing device and to operation of the switches for causing the timing device to change the predetermined intervals to maintain on the average any desired fraction of a car at the dispatching floor.

10. A dispatching system for giving starting signals to a plurality of elevator cars operable past a plurality of floors, comprising a signal device for each of said cars, a timing mechanism for giving dispatching impulses at intervals, means for selecting the next car to receive a starting signal and for preventing the operation of more than one signal device at a time, said means comprising a plurality of chain connected relays adapted to operate repeatedly in a cycle; signal mechanism responsive to arrival of the cars at a predetermined floor, to operation of the selecting means, and to operation of the timing mechanism for operating the signal devices to give starting signals to the cars; and means responsive to operation of said signal mechanism for starting and stopping operation of said chain relays.

WILLIAM F. EAMES. 

